NVM I found how to do it. You have to use the ground costume in the dialogue BEFORE importing the ship costume. If you use it after importing the ship costume, you can't use it anymore for dialogues, since it's not a ground costume anymore.
Oh hooo, good show!
BTW, out of curiousity, anyone got a library of ship costumes that not eveyrone has access too? (Lke the Lockbox and Lobi ships?)